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[martin4556]

   I currently have frontier dsl internet and am using the isp provided modem/router combo and a DIR-655. I have the modem running in bridge mode and the 655 set to PPPoe connection, MTU at 1492. I confirmed the MTU setting on the isp modem/router before bridging it. The question i have is if the router MTU is set to 1492 does everything on the LAN side of the router run at 1492 or does it run at 1500 while the router breaks the packets up? Everything works fine but my pc's all use vista and i'm not sure where to check the mtu settings at and all my game consoles are set to mtu automatic so i can't really see what they're running at either. So I really don't have a problem i'm just curious about this.

[FurryNutz]

For routers, the >MTU is mainly between the ISP modem and the external router and should not effect anything on the LAN side. The MTU value for most Cable ISPs are 1500. Most DSL is between 1472-1492. Always confirm with your ISP on what the correct MTU value should be for your ISP modem. Check the FAQ Library to see if there is some MTU information. I think there is maybe an article about MTU. I can't recall off the top of my head. Or do a search on the Internet for how to check MTU on a PC. Many articles on it.

[martin4556]

 OK, thanks for your reply. I'll do some searches and see what I can find. I was curious about this because on my ISP modem/router combo,under the dsl settings, it is set to 1492 but when i looked at the connected devices page it showed the devices connected at 1500. On this particular modem/router combo I can no longer access the modem statistics once it is in bridge mode and I have no desire to reset it because it was a major pain in the butt to find any info on how to bridge it in the first place. My ISP does not "support" bridge mode and won't answer any questions about it. Again, thanks for your reply.

[Hard Harry]

Well to answer your question, your router will "break up" the packet to what ever you have the MTU set on your ISP modem/router. Its not really breaking it up though unless the packet size that is hitting the router is larger then the MTU. Most gaming is done with UDP which has less overhead and is smaller, so its probably going to be much smaller then 1500 or even 1400 on outbound.  Oh and if you want to get more indepth check this site out.

Now if you want a simple break down of how MTU works, I can give my little metaphor I thought up a while ago. Anyone mind? I think it helps explain it.

[martin4556]

  I believe i just ran across that article and several others while searching. I found out how to find my mtu in vista and it is set at 1500. Apparently from what i read vista uses an auto mtu setting and if you want to change it you have to do it manually. I'm not really concerned with what mt pc's run at as i dont do much with them. I was mainly wondering about my game consoles and what they should be set at. I normally use the auto mtu setting but was just wondering what they should be set at if i did it manually. Like i said, I noticed the difference of the mtu's in the modem/router settings and was just curious as to whether i was creating a possible "bottleneck" in the 655.  Thanks for your response, much appreciated.

[FurryNutz]

What make and model is this ISP Modem?

OK, thanks for your reply. I'll do some searches and see what I can find. I was curious about this because on my ISP modem/router combo,under the dsl settings, it is set to 1492 but when i looked at the connected devices page it showed the devices connected at 1500. On this particular modem/router combo I can no longer access the modem statistics once it is in bridge mode and I have no desire to reset it because it was a major pain in the butt to find any info on how to bridge it in the first place. My ISP does not "support" bridge mode and won't answer any questions about it. Again, thanks for your reply.

[Hard Harry]

Maybe a small bottle neck. I doabt you would see a difference. But if you want, yea, go ahead and set the MTU on the game systems to reflect the MTU of your ISP device. I assume you have a PS3?

[martin4556]

  It's a FRONTIER branded NETGEAR 7550. It's very similiar to a WESTELL 7500. This is the new modem that my isp has started to give out to their customers and there's not a whole lot of info available for it yet. Most searches i did on how to bridge it directed me to dsl reports.com and from there i was able to find a link to a verizon site (frontier has bought verizon's old dsl network) that explained how to bridge the WESTELL 7500 and that is what people who have the new frontier modem are using to put them in bridge mode. I know it's bridged properly because the internet light on the modem is off, internet light is on with the 655 and it  pulls an ISP IP address, not one that would be given out by the ISP router.
   To answer the other question, there are 2 PS3's and 1 XBOX in my house. I will set the mtu on one of the ps3's the next time I have a chance to game.